Air suspension leveling valve



Dec. 8, 1959 J. F. BERTSCH ETAL 2,916,284

AIR SUSPENSION LEVELING VALVE Filed Feb. 26, 1957 v 3 Sheets-Sheet l ZATTORNEY 1959 J. F. BERTSCH ETAL 2,916,284

AIR SUSPENSION LEVELING VALVE Filed Feb.,26, 1957 3 Sheets-Sheet 2 Z4 TTORNE Y Dec. 8, 1959 J. F.. BERTSCH ETAL 2,916,284

, AIR SUSPENSION LEVELING VALVE Filed Feb. 26, 1957 3 Sheets-Sheet 3 w: arc/elven United States Patent O AIR SUSPENSION LEVELING VALVE Application February 26, 1957, Serial No. 642,591 9 Claims. Cl. 267-65 This invention relates to pneumatic suspension and more particularly to control mechanism for introducing and exhausting air from pneumatic springs so as to maintain a constant relative displacement between the sprung and uusprung portions associated with the spring.

Devices for regulating the standing height of vehicles equipped with pneumatic suspension are commonly referred to as-leveling valves. In the prior art, leveling valves have generally fallen into two principal classes. By far the most common type of leveling valve is mounted on the sprung mass adjacent the air spring and provided with suitable linkage connections with the unsprung mass so that the valve mechanism is moved from a neutral position to either an intake or exhaust position responsive to corresponding variations in displacement of the relatively movable portions of the spring. It has also been proposed to dispose both the leveling valve and its associated operating connections entirely internal- 1y of the air spring. While the latter system offers severnl distinct advantages such as maximum protection of the operating parts, elimination of a conduit from the valve body to the spring, and elimination of certain pres sure seals-in the valve casing, the various forms of internal leveling valves in the prior art possess certain inherent shortcomings and limitations which seriously detract from their usefulness as a practical matter. Foremost among the disadvantages of internal leveling valves known heretofore is the difficulty, if not impossibility, in performing service or adjustments thereon without dismantling the entire spring assembly. "Further, known types of internal valves have, without exception, involved operating mechanisms which were either unreliable due to impositive driving connections, or exceedingly difiicult to install initially.

An objectof. the present invention is to provide an air spring leveling valve structure in which is combined the convenience and accessibility of external leveling valves with the several technical advantages of internal leveling valves.

A further object is to provide a leveling valve structurewhich is mounted in direct communicating relation with the air spring in such a way that all service functions may be performed without access to the interior of the spring.

Another object is to provide an air spring leveling valve which is mounted exteriorly of and directly on the air spring and provided with an operating structure disposed internally of the spring.

A still further object is to provide a leveling valve construction of the stated character wherein the operating structure comprises a resiliently biased follower arm which is adapted to rotate through a predetermined angular path responsive, to displacement of the uusprung portion of the spring relative to the sprung portion.

, Still a further object is to provide a leveling valve of the type described wherein the valving mechanism is adapted for angular adjustment about the axis of rotation of the follower arm operating mechanism in order to per- Patented Dec. 8, 1959 mit initial regulation of the standing height of the vehicle.

These and other objects, advantages and features of the invention will become more fully apparent as reference is had to the accompanying specification and drawings wherein:

Fig. l is a view of a typical vehicle air spring incorporating a leveling valve construction according to the present invention;

Fig. 2 is an enlarged fragmentary view, partly in section, showing the internal mechanism of the leveling valve shown in Fig. 1;

Fig. 3 is an enlarged fragmentary view, partly in section, similar to Fig. 2 showing the relative positions of the valve parts when the air spring is collapsed to a position requiring introduction of air therein;

Fig. 4 is a top plan view, partly in section, looking in the direction of arrows 44 of Fig. 1; and

Fig. 5 is an enlarged fragmentary view, partly in section, looking in the direction of arrows 5-5 of Fig. 1.

Referring now to the drawings and particularly Fig. 1, there is illustrated an air spring assembly in which the reference numeral 2 designates generally an inverted cup shaped dome which in vehicle suspension is rigidly afiixed to the sprung portion of the vehicle, not shown, usually the frame. Extending upwardly into dome 2 is a generally cylindrical piston 4 which in the illustrated embodiment is rigidly secured to a support 6 which, in turn, forms an integral part of the vehicle wheel suspension arm, not shown, so that piston 4 reciprocates in dome 2 responsive to vertical wheel oscillation. In order to form a deformable air confining cavity between dome 2 and piston 4, there is provided an annular flexible diaphragm 8 which has a beaded outer periphery 10 supported at the lower terminal lip 12 of dome 2 by-means of a ring flange 14. Ring 14, in turn, is supported on dome 2 by spinning over the lip 12. The inner periphery of diaphragm 8 is provided with an enlarged bead 16 of irregular cross section which is adapted for snap-on engagement with the upper inwardly curled edge 18 of piston 4. Disposed over the aperture formed by head 16 and covering the top end of piston 4 is a metal cap structure 20 having a depending portion 21 which is adapted for snap-in engagement with the inner circular wall 22 of bead 16.

I In order to introduce and regulate the volume of air confined by the air spring assembly, there is provided a leveling valve structure 24 which is adapted to introduce or exhaust air from the spring. As seen in Fig. 1, valve 24 is provided with a pair of conduits 26 and 28 which respectively communicate with a high pressure air supply tank, not shown, and a low pressure air return tank, not shown. In operation; valve 24 provides open communication between high pressure tank and the interior of the spring assembly whenever the vertical displacement of dome 2 and piston 4 decreases beyond a predetermined limit and to provide open communication with the low pressure tank whenever the relative displacement exceeds the predetermined limit. To this end, valve 24 is formed with a valve body 30 (Fig. 4) having parallel drilled orifices 32 and 34, each of which communicates at one end with conduits 26 and 28. At their opposite ends drilled passages 32 and 34 communicate with right angled passages 36 and 38 which, in turn, communicate with orifices 40 and 42 which are threaded into the milled faces 44 of a boss 46. Orifices 40 and 42 communicate with the interior cavity 48 of leveling valve housing 50. Housing 50, in turn, has an annular neck 52 which is threadably secured in the wall 54 of dome 2. A pair of drilled passages 56 and 58 permit communication between cavity 48 and the interior of the spring assembly. In order to control passage of air through orifices 40 and 42 valve body 30 has press fitted therein a stub shaft 60 which is disposed between orifices '40 and 42- andperpendicular thereto. Rotatably mounted on shaft 60 are a pair of oppositely extending wing-like valve closure members 62 and 64. Each closure member 62 and 64, in turn, is provided with a circular rubber-like disk-66 and 68 which is adapted for abutting'engagement'with the open end of its associated orifice 40 and 42. Closure members 62 and 64 are normally biased clockwise and counterclockwise, respectively, by means of 21 double ended coil torsion spring 70, the opposite ends of which engage the bottom walls 72 and 74 of 'the respective closure members. Disposed in the hollow neck 52f'of valve housing 50 in axial alignment with'stub shaft-60 is a valve operating shaft 76. At its outer end 78,- shaft 76 is conical in cross section and has an axial bore 80 formed therein which is adapted to receive the outer end of stub shaft 60. Rigidly attached to the face ofconical portion 78 is a bifurcated lever 82, the opposite ends 84 and 86 of which are bent-at right angles to the'cen'tral portion 88 to extend in overlapping relation'with the'top surface of outer extremities 90 and 92 of valve closure members 62 and 64. At its inner end, shaft 76 isiprovided with a knurled portion 94 to which-isconnected a curved lever 96. At its free end, lever 96 is provided with a nylon roller 98 which is adapted for rolling engagement with the top wall 100 of the'snap-in cap 20 carried by piston 4. To maintain roller 98 of follower lever 96 in rolling contact with cap 20, there is provided a single acting coiled torsion spring 102, which is connected at one end 104 to lever 96 while its opposite end 106 abuts the inner side wall of dome 2. Follower lever 96 is so formed and dimensioned that roller 98 substantially traverses cap 20 as lever 96 swings upwardly or downwardly about the axis of shaft 76 to follow the reciprocating movement of piston 4.

As will be evident particularly from Fig. 5, when follower lever 96 is swung in a counterclockwise direction responsive to upward movement of piston 4, shaft 76 will rotate in a corresponding direction and cause the end 84 of bifurcated lever 82 to urge the intake valve closure member 62 counterclockwise relative to intake orifice 40 and thereby place the interior of the spring assembly in open communication with the high pressure tank via conduit '26. As air enters the spring assembly through the open intake valve, the relative displacement of dome 2 and piston 4 will progressively increase while follower lever 96 simultaneously rotates in a clockwise direction due to counterclockwise pressure of torsion spring 102 which maintains the roller 98 in constant contact with cap 20. As soon as the predetermined displacement between dome 2 and piston 4 has been achieved, the angular movement of follower lever 96 will have rotated shaft 76 and bifurcated lever arm 82 to a position permitting intake valve closure member 62 to block the flow of air through orifice 40 responsive to-pressure of spring 70. As long as the predetermined relative displacement is maintained, no additional air will be admitted through in"- take orifice 40 or emission through exhaust orifice 42. However, should the relative displacement between dome 2 and piston 4 exceed the predetermined limit, follower lever 96 will resume clockwise movement responsive to spring 102 to maintain roller 98 in continuing contact with cap 20. Thereupon the end 84 of bifurcated lever 82 will urge exhaust valve closure member64 away from exhaust orifice 42 and permit emission of air from the spring assembly to the low pressure tank via conduit 28 until the predetermined relative displacement is restored, at which time the angular position of lever 82 will permit exhaust valve closure 64 to block orifice 42.

Particular attention is directed to the improved and simplified means of correlating the positions of. valve closures 62 and 64 to correspond with the relative verti cal position of piston 4 in dome 2. It will be evident'that follower lever 96 and roller 98 assure positive uniform rotation of shaft 76 in both a clockwise and a" counterclockwise direction responsive to vertical movement of piston 4 throughout the latters normal range of vertical movement. However, in the event of excessive rebound movement of piston 4, roller 98 need not necessarily remain in contact with cap 20. In addition, because each valve closure member 62 and 64 is capable of angular movement substantially in excess of from their closed position, follower arm 96 will tolerate excessive compression movement'of piston 4 without affecting normal functioning of the leveling valves through the normal range of movement of piston 4. Because of the mode of effecting synchronous driving engagement between intake and exhaust valves and the piston 4, difficulty of initial installation of the air spring assembly is minimal. Thus, the follower'arm 96, shaft 76 and valve housing 50 may be installed as a unit in dome 2 prior to assembly of piston 4 and diaphragm 8. After the spring is completely assembled, valve body 30 is then disposed over theopen outer face of housing 50 and secured thereto by means of machine bolts 108 which extend through arc'uate slots 110 in valve body 30 and engage the valve housing 50. Since arcuate slots 110 permit limited angular movement of valve body 30, it will be evident that precise adjustment of the desired standing height of a vehicle may be readily accomplished by slightly loosening bo'lts 108 and rotating the valve body either clockwise or counterclockwise as the case may be. In addition, should inspection, minor repairs or replacement of valve parts be required, the entire mechanism is not only readily accessible but may be removed and replaced without disturbing the valve housing and follower lever mechanism inte'riorly of the springs.

From the foregoing it will be seen that the present invention affords all the advantages of a fully external leveling va'lve while eliminating the danger of damage to exposed operating linkage as is the case with fully external valves. Similarly, the follower lever drive mechanism offers all the advantages of internal leveling valves known heretofore while eliminating the complexity, difiiculty of assembly and unreliability usually associated with such mechanisms. 7

While but one embodiment of the invention has been shown and described, it will be evident that other changes and modifications may be made therein. It is, therefore, to be understood that it is not intended to limit the invention to the embodiment shown, but only by the scope of the claims which follow.

We claim:

1. A valve assembly for controlling flow of fluid into and out of a fluid spring of the piston and cylinder type, said valve assembly compriing a valve housing disposed exteriorly of said cylinder and communicating with the interior thereof, a valve body mounted in said housing, anintake valve and an exhaust valve associated with said body, rotary means arranged in one-way driving engagement with said intake valve and exhaust valve respectively, a lever disposed interiorly of said spring and connected to said rotary member, and means on the free end of said lever effecting follower engagement with said piston whereby movement'of the latter in one direction causes said rotary member to open said intake and movement of said piston in the other direction causes said rotary member to open said exhaust valve. 7

2. A valve assembly for controlling flow of compressible fluid into and out of a fluid spring of the type including two relatively movable'rigid members and a'flexible' body connecting said members, said valve assembly comprising a valve housing disposed exteriorly of one of s'aid members and communicating with the interior of said spring, 'a valve body mounted in said housing, an intake and an exhaust valve associated with said body, rotary means including intake and exhaust valve engaging portions, a lever disposed interiorly of said spring and connected to said rot'a'ry member, and means onthe free end" ofsaidlever' efiecting follower engagement with the other of said members whereby movement of the latter in one direction causes said rotary member to open said intake and movement of said piston in the other direfition causes said rotary member to open said exhaust v ve.

3. A leveling valve assembly for controlling the flow of compressible fluid into and out of a fluid spring of the piston and cylinder type, said valve assembly comprising a valve housing disposed exteriorly of said cylinder and communicating with the interior thereof, a valve body mounted in said housing, an intake and an exhaust valve associated with said body, rotary means including intake and exhaust valve displacing portions, a lever disposed in said spring and connected to said rotary member, means on the free end of said lever effecting follower engagement with said piston whereby movement of the latter in one direction causes said rotary member to open said intake valve and movement thereof in the other direction causes said rotary memher to open said exhaust valve, and resilient means urglng said lever in a direction providing yielding engagement with said piston.

4. A leveling valve assembly for controlling the flow of compressible fluid into and out of a fluid spring of the piston and cylinder type, said valve assembly comprising a valve housing disposed exteriorly of said cyl- 1nder and communicating with the interior thereof, a valve body mounted in said housing, an intake and an exhaust valve associated with said body, a rotary member engaging said intake and exhaust valves and having portions thereon adapted to displace said valves alternately, a lever disposed in said spring and connected to said rotary member, a roller on the free end of said lever effecting follower engagement with the top of said piston whereby movement of the latter in one direction causes said rotary member to open said intake valve and movement thereof in the other direction causes said rotary member to open said exhaust valve, and resilient means urging said lever in a direction providing yielding engagement of said roller with said piston.

5. A leveling valve assembly for fluid springs of the type including a piston and cylinder, said assembly comprising a valve housing extending through and threadably engaging the wall of said cylinder, a shaft rotatably mounted in said housing, a follower lever connected to said shaft and having its free end abuttingly engaging said piston, resilient means acting on said lever to maintain the free end thereof in yielding engagement with said piston throughout the normal range of movement of the latter, a valve body secured to an exterior face of said valve housing to form a closed cavity therein, said body having an integral portion extending into said cavity, an intake and exhaust valve orifice formed in said last mentioned portion, a pair of valve closures swingably mounted in said housing engageable respectively with said intake and exhaust orifices, resilient means engaging said closures to urge the latter to orifice closing positions, means connected to said shaft and engageable with said closures upon rotation of said shaft to selectively open either said intake or exhaust orifice, and means for rotatably adjusting said valve body relative to said housing to correlate the closed positions of said valves with a predetermined relative displacement of said piston and cylinder.

6. A leveling valve assembly for fluid springs of the type including a piston and cylinder, said assembly comprising a valve housing having an elongated neck portion extending through and threadably engaging the wall of said cylinder, a shaft rotatably mounted in said housing, a follower lever connected to said shaft, a roller on the free end of said lever engaging said piston, resilient means acting on said lever to normally maintain said roller in yielding engagement with said piston, a valve body secured to an exterior face of said valve housing to form a closed cavity therein, said body having an integral portion extending into said cavity, a pair of spaced orifices mounted in said last mentioned portion, intake and exhaustports communicating with said orifices, a pair of valve closures swingably mounted in said housing coaxial with said rotatable shaft and engageable respectively with said intake and exhaust orifices, resilient means engaging said closures to urge the latter in opposite directions to effect closing of said orifices, a bifurcated arm rigidly connected to said shaft and having its opposite ends arranged to angularly displace said closures upon rotation of said shaft in opposite directions to selectively open either said intake or exhaust orifice, and means for effecting angular adjustment of said valve body relative to said housing to correlate the closed positions of said valves with a predetermined relative displacement of said piston and cylinder.

7. A leveling valve assembly for fluid springs of the type including a piston and cylinder, said assembly comprising a valve housing having an elongated neck portion extending through and threadably engaging the wall of said cylinder, a shaft rotatably mounted in said housing, a follower lever connected to said shaft, a roller on the free end of said lever engaging said piston, resilient means acting on said lever to normally maintain said roller in yielding engagement with said piston, a valve body secured to an exterior face of said valve housing to form a closed cavity therein, said body having an integral portion extending into said cavity, a pair of spaced orifices mounted in said last mentioned portion, intake and exhaust ports communicating with said orifices, a pair of valve closures swingably mounted on a valve body supported shaft coaxial with said rotatable shaft and engageable respectively with said intake and exhaust orifices, resilient means engaging said closures to urge the latter in opposite directions to effect closing of said orifices, a bifurcated arm rigidly connected to said shaft and having its opposite ends arranged to angularly displace said closures upon rotation of said shaft in opposite directions to selectively open either said intake or exhaust orifice, and means for effecting angular adjustment of said valve body relative to said housing to correlate the closed positions of said valves with a predetermined relative displacement of said piston and cylinder.

8. The structure defined in claim 6 wherein said valve closures include resilient pads arranged to abut said orifices.

9. The structure defined in claim 6 wherein said resilient means engaging said closures comprising a torsionally biased coil spring having one of each of its free ends abutting said one of each of said closures respectively.

References Cited in the file of this patent UNITED STATES PATENTS 

